Circuit breaker closing mechanisms



May 11, 1965 R. E. FRINK ETAL 3,183,332

I CIRCUIT BREAKER CLOSING MECHANISMS Filed Aug. 9, 1962 7 Sheets-Sheet 1INVENTQRS Russell E. Frank 8 Paul Olsson ATTORNEY May 11, 1965 R. E.FRINK ETAL CIRCUIT BREAKER CLOSING MECHANISMS Filed Aug. 9, 1962 7Sheets-Sheet 2 May 11, 1965 R. E. FRINK EI'AL 3,183,332

CIRCUIT BREAKER CLOSING MECHANISMS Filed Aug. 9, 1962 7 Sheets-Sheet 3May 1965 R. E. FRINK ETAL CIRCUIT BREAKER CLOSING MECHANISMS 7Sheets-Sheet 4 Filed Aug. 9, 1962 mm mm May 11, 1965 R 5 mm ETAL3,183,332

CIRCUIT BREAKER CLOSING MECHANISMS Filed Aug. 9, 1962 7 Sheets-Sheet 5May 11, 1965 R. E. FRINK ETAL 3,183,332

CIRCUIT BREAKER CLOSING MECHANISMS Filed Aug. 9, 1962 7 Sheets-Sheet 6May 11, FRINK T CIRCUIT BREAKER CLOSING MECHANISMS Filed Aug. 9, 1962 '7Sheets-Sheet 7 United States Patent CHRCUET BREAKER CLGSING MECHANZSRISRussell E. Frink, Forest Hilts, and Paul ()lssen, Penn TownshirAllegheny County, Pa., assignors to Westinghouse Electric Corporation,East Pittsburgh, Pa., a corporation of Pennsylvania Filed Aug. 9, 1962,Ser. No. 215,854 19 Claims. (Cl. 20i)153) This invention relates,generally, to closing mechanisms for circuit breakers and, moreparticularly, to mechanisms of a type in which energy for closing acircuit breaker is stored in a spring.

Numerous closing mechanisms of the spring storedenergy type have beenconstructed heretofore. However, the prior mechanisms have beencomplicated in structure and operation. Furthermore, they have not beensuitable for operating circuit breakers of a relatively large size.

An object of this invention is to provide a stored-energy closingmechanism which shall be simple in construction and efiicient inoperation and which may be economically manufactured and installed.

A more specific object of the invention is to provide a stored-energyclosing mechanism which is trip-free.

Another object of the invention is to provide a closing mechanism inwhich energy may be stored in a spring by electrically operated means orby manually operated means.

A further object of the invention is to provide for reducing shock onthe mechanism during both closing and opening of the breaker.

Other objects of the invention will be explained fully hereinafter orwill be apparent to those skilled in the art.

In accordance with one embodiment of the invention, energy is stored ina spring by means of a crankshaft which is driven by a motor through aratchet and pawl device. When the stored energy is released, thecrankshaft drives a cam, secured to the shaft, to extend a toggle systemwhich drives a trip-free shaft to close the contact members of thecircuit breaker. The toggle system includes only two links, one of whichis always under tension and is attached directly to the tripping latchassembly to provide trip-free operation. A spring and dashpot assemblreduces shock on the mechanism during both closing and opening of thebreaker.

For a better understanding of the nature and objects of the invention,reference may be had to the following detailed description taken inconjunction with the accompanying drawings, in which:

FIGURE 1 is a view, in front elevation, of a circuit breaker closingmechanism embodying the principal features of the invention;

FIG. 2 is a view, in top plan, of the mechanism shown in FIG. 1;

PEG. 3 is a View, partly in left side elevation and partly in section,of the mechanism;

FIG. 4 is a view, in right side elevation, of the mechanism;

FIG. 5 is a view, partly in section and partly in elevation, of aportion of the mechanism shown in FIG. 1;

FIGS. 6 to 9, inclusive, are detail views showing different operatingpositions of parts of the closing mechanism; and

FIG. 10 is a View, partly in section and partly in elevation, of anaccelerating spring and dashpot assembly utilized in conjunction withthe mechanism.

Referring to the drawings, the spring stored-energy mechanism showntherein is suitable for use with a relatively high voltage magnetic aircircuit breaker, such as the type DH circuit breaker manufactured by theWestinghouse Electric Corporation. However, with slight modifiicecation, the mechanism can be applied to circuit breakers of other types.

As shown, the mechanism is supported by a frame 11 which may be attachedto the frame of the circuit breaker (not shown). Generally, themechanism comprises a trip-free shaft 12, a closing spring 13, acrankshaft 14, a ratchet mechanism 15, a motor 16, a toggle linkage 17,a cam 13, and an accelerating spring and dashpot assembly 19. Thetrip-free shaft 12 is rotatably mounted in bearings 21 disposed in theframe 11. An operating lever 22 is secured to each end of the shaft 12.A third operating lever 23 is secured to the middle portion of the shaft12. Operating members 24 are pivotally attached to the operating leversby means of pins 25. The operating members 24 are attached to themovable contact members (not shown) of the circuit breaker to actuatethe contact memhere. The operating levers 22 each have a lower arm 26utilized for a purpose which will be described hereinafter.

As shown most clearly in FIG. 4, one end of the closing spring 13 restsin a spring seat 27 provided in the frame 11. The other end of thespring 13 engages a spring retainer 28 which is retained on a rod 29 bymeans of a pin 31. The rear end of the rod 29 is supported by a link 32,one end of which is attached to the rod 29 by the pin 31 and the otherend of which is pivotally attached to the frame of the circuit breaker(not shown). The other end of the rod 29 is threaded into a block 33,thereby permitting the effective length of the rod to be adjusted tovary the amount which the spring 13 is compressed between the springseat 27 and the retainer 28. The block 33 is attached to a crank pin 34which is carried by a crank lever 35 attached to one end of thecrankshaft 14. As shown in FIG. 4, the spring 13 is in its most relaxedposition. When the crank lever is rotated from the position shown, thespring 13 is fully charged.

The ratchet mechanism 15 comprises a ratchet wheel 36, an actuator 37, apawl carried by the actuator 37, and an additional pawl 3% pivotallymounted in the frame 11 by means of a pin 41. The ratchet whee 36 issecured to the end of the shaft 14 opposite the crank lever 35. Thewheel 36 has a plurality of teeth disposed around a portion of itsperiphery. The actuator 37 pivots on the shaft 14 and is biased towardan eccentric 43 by a tension spring 44. A roller 45, carried by theactuator 37, engages the eccentric 43. The pawl 38 is biased toward theratchet wheel 36 by means of a torsion spring 46. The pawl 39 is alsobiased toward the ratchet wheel 36 by means of a torsion spring 47.

The motor lid drives a shaft 48 through spur gears and 51. The eccentric43 is secured to the shaft 45 Thus, when the motor 16 runs, the ratchetwheel 36 is advanced one tooth for each revolution of the shaft 43 inthe clockwise direction, as viewed in PEG. 3, by means of the actuator37 and the pawl 38. The pawl 39 prevents the wheel 35 from rotatingbackwards between strokes of the actuator 37. The last tooth on theratchet wheel carries the crank lever 35 just over center in the springcharged position, and the force of the main spring 13 brings a roller52, carried by the crank lever 35, against a closing latch 53 as shownin FIG. 7. In this position, there are no more teeth on the ratchet wheefor the pawl 38 to engage and the motor L6 runs free until it isshutoff.

The toggle linkage 17 comprises links which are pivotally attached tothe operating lever 23 by means of a pin 55, and a link 56, one end ofwhich is pivotally attached to the links 54 by means of a pin 57. Tworollers 58 are also mounted on the pin 57.

As shown most clearly in FIGS. 5 to 9, the other end of the link 56 ispivotally attached to a tripping latch assembly 59. The assembly 5hcomprises a cam 61 pivoted on a pin 62, a rocker arm 63 pivoted on a pin64, and :a trip latch 65 pivoted on a pin 66. The one end of the link 56is pivotally attached to the cam 61 by means of a pin 67. The rocker:arm 63 is biased toward the cam 61 by a torsion spring (not shown). Thelatch 65 is biased toward the rocker arm 63 by a torsion spring (notshown). The toggle linkage 17 is so constructed that the link 56 isunder tension when the rollers 58 are engaged by the cam 18. A tensionspring 711 is stretched between the pin 57 of the toggle linkage and theframe 11.

As previously stated, the cam 13 is secured to the crankshaft -14. Thecrank lever 35 and the ratchet wheel 36 are also secured to thecrankshaft 14.

As shown more clearly in FIG. 10, each accelerating spring and dashpotassembly. 19, of which two are provided, comprises a shaft 72, a springretainer 73, la cylinder 74, a piston 75 and accelerating springs 76 and77. A rod end is secured to one end of the shaft 72. The rod end 78 ispivotally attached to the lower portion 26 of one of the operatinglevers 22 which, as previously explained, are secured to the shaft 12.The rod end 73 is attached to the lever portion 26 by .a pin 79. One endof the cylinder 74 is pivotally attached to a bracket 81 by means of apin 82. The bracket 81 is attached to the frame 11. The piston 75 isattached to one end of the shaft 72 by a pin 83. An opening 84 extendsthrough the piston '75. The spring retainer '73 is attached to the shaft72 by a pin 85. The spring retainer 73 is cast with a key shaped openingwhich cooperates with the pin so that rotating the retainer screws theshaft into or out of the rod end 78 to adjust the breaker contact openposition. The spring 77 is disposed between the retainer 76 and thecylinder 74. One end of the spring 76 engages the retainer '75 and theother end surrounds the cylinder 74, and in the partially closedposition engages lugs 68 around the periphery of the cylinder to.provide high initial opening acceleration.

As shown, openings 96 are provided in one end of the cylinder 74. Theseopenings are closed by valves 97 which are biased to the closed positionby relatively light springs 69.

The operation of the mechanism may be best understood by referring toFIGS. to 9, inclusive. Assuming that the breaker is open and the spring'13 discharged, the crank lever 35 is as shown in FIG. 6, the cam 16,the operating lever 23, the tripping latch assembly 59 and aspring-biased latch 86 are as shown in FIG. 9. The latch 86 pivots on apin 87 and is biased toward the crankshaft 1-4 by a spring 83. When themotor 16 is energized, it operates the ratchet mechanism to drive thecrankshaft 14, thereby charging the spring 13. As previously explained,When the spring is charged, the roller 52, carried by the crank lever35, engages the closing latch 53 as shown in FIG. 7. At this time, thecam 18, the lever :23 and the tripping latch assembly 59 are as shown inFIG. 8, having been reset by the spring 71. The pressure of the roller52 against the sloping surface of the latch 53 biases the latch in acounterclockwise direction against a roller 96 carried by a closingtrigger 91. The trigger 9 1. is biased in a counterclockwise directionabout its pivot 92 by a spring 93. Lifting the trigger 91 releases thelatch 5-3 and the closing spring 13 rotates the crank lever and the cam18 in -a counterclockwise direction to close the breaker as shown inFIG. 5. In this position, the toggle link-v age 17 is fully extended.

During its upward movement, the roller 58 has pushed the latch 86 to theleft and the latch drops under the tension, thereby tending to rotatethe cam 61 in a counterclockwise direction. Lifting the trip latch 65releases the cam 61 so that the roller 58 runs out on the cam 13, asshown in FIG. 9, or off of the latch 36 if the spring 13 is recharged,thereby permitting the linkage to reset as shown in FIG. 8. It will beunderstood that the trip latch 65 land the closing latch 91 may beoperated in any manner well known in the art to control the tripping andthe closing of the circuit breaker.

As previously explained, the entire linkage system is so constructedthat at all points of the closing stroke, the link 56 is under tension.Thus, if the trip latch 65 is released, the breaker will openirrespective of the position of the cam 18. In this manner the breakeris made trip-free at all times. The toggle linkage is permitted tocollapse to the position shown in FIG. 9 whenever the trip latch 65israised to release the cam 61. It will be understood that the cam 18and the linkage mechanism may be so constructed that the torces appliedto the linkage match the forces required by the circuit breaker duringthe closing operation. As shown, the cam has an increasing lobe portionwhich applies pressure on the links 54 to close the breaker.

The satisfactory operation of a relatively high voltage circuit breakerwith one pair of contacts per pole requires extremely high contactwelocity during opening of the breaker. Tests on a breaker of one typehave shown that a travel of seven inches is required in the first cycleafter the contact members separate. In order to accomplish this, aninitial accelerating torque of 30,000 inch pounds is required. Thefunction of the accelerating spring and dashpot assembly 19 is toprovide the required accelerating torque during opening and to reduceshock on the mechanism during both opening and closing of the breakercontact members. 7

As previously explained, two of the a ssemblies 19 are provided, onebeing attached to each one of the operating levers 22. The operation ofthe assembly :19 will be best understood by referring to FIG. 10. Whenthe breaker is closed, the pin 79 moves the shaft or rod 72 and thepiston 75 to the right. 7 This compresses the springs 76 and 77. It willbe understood that the closing spring 13 must have suflicient strengthto compress the springs 76 and 77 while the contact members of thecircuit breaker are being closed. When the piston 75 passes a portholein the center of the cylinder 74, the trapped air attempts to flowthrough holes 96 in the rear end of the cylinder 74. However, the aircloses valves 97 more tightly, thereby compressing the air. Thecompressed air must exhaust through the leak hole 84 in the piston 75.This cushions the closing shock. A sealing member 98 c0mpressed by aspring 99 around the rod 72 prevents air from escaping around the pistonrod.

During opening of the breaker, the accelerating spring 76 and 77 rotatethe lever 26 clockwise and the piston 75 moves to the left. The suctionof the piston opens the valves 97 so that air can enter the cylinderbehind the piston. When the piston passes the port 95, air is trapped tothe left of the piston, compressed and permitted to escape through theleak hole 84. This cushions the latter part of the opening stroke andprevents excessive rebound of the contact members of the circuitbreaker. Thus, shock on the mechanism is reduced during both closing andopening of the circuit breaker.

As previously explained, the operation of the' circuit breaker duringclosing andopening may be controlled in a manner well known in the art.Furthermore, the

7 operation of the motor 16 may be controlled by limit roller in thebrea ker'closed position so that the crankshaft 14 and the cam 18 can berotated counterclockwise to recharge the spring 13 while the breakerremains closed. As previously explained, the spring 13 is charged byenergizing the motor 1-6 to operate the ratchet mechanism 15. V V e Inthe position shown in- FIG. 5, the link 56 is under switches of a typewell known in the art; The ratchet mechanism may be operated manually tocharge the spring 13 if it becomes necessary to do so. 7

From the foregoing description, it is apparent that the inventionprovides a spring "stored-energy mechanism which is suitable foroperating a circuit breaker. The

circuit breaker is trip free at all times during the closing operation.The mechanism is simple in construction and ei'ficient in operation.

Since numerous changes may be made in the abovedescribed constructionand different embodiments of the invention may be made Without departingfrom the spirit and scope thereof, it is intended that all the mattercontained in the foregoing description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

We claim as our invention:

1. A stored-energy mechanism comprising a frame, a trip-free shaftrotatably mounted in the frame, a closing spring, a crankshaft rotatablymounted in the frame, means for driving the crankshaft to charge thespring, closing latch means for releasably retaining the spring in thecharged condition, cam means driven by the crankshaft when said closinglatch means is released to release said spring, tripping latch means,toggle means connected between the tripping latch means and thetrip-free shaft, and said toggle means being extended by said cam meansto rotate the trip-free shaft when the closing latch means is releasedto release the energy stored in said spring.

2. A stored-energy mechanism comprising a frame, a trip-free shaftrotatably mounted in the frame, a closing spring, a crankshaft rotatablymounted in the frame, means for driving the crankshaft to charge thespring, closing latch means for releasably retaining the spring in thecharged condition, an operating lever secured to the tripfree shaft,tripping latch means, toggle means having one link connected to thetrip-free shaft and another link connected to the tripping latch means,and cam means driven by the crankshaft to extend the toggle means torotate the trip-free shaft when the closing latch means is released torelease the energy stored in said sprin 3. A stored-energy mechanismcomprising a frame, a trip-free shaft rotatably mounted in the frame, aclosing spring, a crankshaft rotatably rnounted in the frame, means fordriving the crankshaft to charge the spring, closing latch means forreleasably retaining the spring in the charged condition, tripping latchmeans, toggle means having one link connected to the tripfree shaft andanother link connected to the tripping latch means, cam means driven bythe crankshaft to extend the toggle means to rotate the trip-free shaftwhen the closing latch means is released to release the energy stored insaid spring, and said tripping latch means being releasable to preventthe cam means from rotating the trip-free shaft.

4. A stored-energy mechanism comprising a frame, a trip-free shaftrotatably mounted in the frame, a closing spring, a crankshaft rotatablymounted in the frame, means for driving the crankshaft to charge thespring, closlatch means for releasably retaining the spring in thecharged condition, tripping latch means, toggle means having one linkconnected to the trip-free shaft and another link connected to thetripping latch means, cam means secured to the crankshaft to extend thetoggle means to rotate the trip-free shaft when the closing latch meansis released, and said tripping latch means being releasable to collapsethe toggle means.

5. A stored-energy mechanism comprising a frame, a trip-free shaftrotatably mounted in the frame, a closing spring, a crankshaft rotatablymounted in the frame, means for driving the crankshaft to charge thespring, closing latch means for releasably retaining the spring in thecharged condition, an operating lever secured to the trip-free shaft,tripping latch means, toggle means having a first link and a second linkpivotally connected together, one end of the first link being pivotallyattached to said operating lever, one end of the second link beingpivotally attached to the tripping latch means, cam means secured to thecrankshaft, and said cam means being driven by the spring to extend thetoggle means to rotate the tripfree shaft when the closing latch meansis released.

6. A stored-energy mechanism comprising a frame, a trip-free shaftrotatably mounted in the frame, a closing spring, a crankshaft rotatablymounted in the frame, means for driving the crankshaft to charge thespring, closing latch means for releasably retaining the spring in thecharged condition, an operating lever secured to the trip-free shaft,tripping latch means, toggle means having a. first link and second linkpivotally connected togethcr, one end of the first link being pivotallyattached to said operating lever, one end of the second link beingpivotally attached to the tripping latch means, cam means secured to thecrankshaft, said cam means being driven by the spring to extend thetoggle means to rotate the tripfree shaft when the closing latch meansis released, and said tripping latch means being releasable to collapsesaid toggle means.

7. A stored-energy mechanism comprising a frame, a trip-free shaftrotatably mounted in the frame, a closing spring, a crankshaft rotatablymounted in the frame, means for driving the crankshaft to charge thespring, closing latch means for releasably retaining the spring in thecharged condition, an operating lever secured to the trip-free shaft,tripping latch means, toggle means having a first link and a second linkpivotally connected together, one end of the first link being pivotallyattached to said operating lever, one end of the second link beingpivotally attached to the tripping latch means, cam means secured to thecrankshaft, said cam means being driven by the spring to extend thetoggle means to rotate the trip-free shaft when the closing latch meansis released, said second toggle link being under tension duringextension of the toggle means, and said tripping latch means beingreleasable to release said tension and collapse the toggle means.

8. In a stored-energy mechanism for actuating contact members of acircuit breaker, in combination, a frame, a trip-free shaft rotatablymounted in the frame, a plurality of operating levers secured to theshaft, operating means for connecting said levers to the breaker contactmembers, a closing spring, a crankshaft rotatably mounted in the frame,a ratchet wheel secured to the crankshaft, a pivoted actuator fordriving the ratchet wheel and the crankshaft to charge the spring, amotor for oscillating the actuator, closing latch means for releasablyretaining the spring in the charged condition, tripping latch means,toggle means connected between the tripping latch means and one of theoperating levers on the trip-free shaft, and cam means driven by thecrankshaft to extend the toggle means to rotate the trip-free shaft andto close the contact members of said circuit breaker when the closinglatch means is released to release the energy stored in said spring.

9. in a stored-energy mechanism for actuating contact members of acircuit breaker, in combination, a frame, a trip-free shaft rotatablymounted in the frame, a plurality of operating levers secured to theshaft, operating means for connecting said levers to the breaker contactmembers, a closing spring, a crankshaft rotatably mounted in the frame,a ratchet Wheel secured to the crankshaft, a pivoted actuator fordriving the ratchet Wheel and the crankshaft to charge the spring, amotor for oscillating the actuator, closing latch means for releasablyretaining the spring in the charged condition, tripping latch means,toggle means connected between the tripping latch means and one of theoperating levers on the trip-free shaft, cam means driven by thecrankshaft to extend the toggle means to rotate the trip-free shaft andto close the contact members of said circuit breaker when the closinglatch means is released to release the energy stored in said spring, andsaid tripping latch means being releasable to prevent the cam means fromrotating the trip-free shaft.

10. a stored-energy mechanism for actuating contact members of a circuitbreaker, in combination, a frame, a trip-free shaft rotatably mounted inthe frame, a plurality of operating levers secured to the shaft,operating cans for connecting said levers to the breaker contactmembers, a closing spring, a crankshaft rotatably mounted in the frame,a ratchet wheel secured to the crankshaft, a pivoted actuator fordriving the ratchet wheel and the crankshaft to charge the spring, amotor for oscillating the actuator, closing latch means for releasablyretaining the spring in the charged condition, tripping latch means,toggle means connected between the tripping latch means and one of theoperating levers on the trip-free shaft, cam means driven by thecrankshaft to extend the toggle means to rotate the trip-free shaft andto close the contact members of said circuit breaker when the closinglatch means is released to release the energy stored in said spring, anda spring-biased latch for retaining the toggle means in its extendedposition.

11. In a stored-energy mechanism for actuating contact members of acircuit breaker, in combination, a frame, a trip-free shaft rotatablymounted in the frame, a plurality of operating levers secured to theshaft, operating means for connecting said levers to the breaker contactmembers, a closing spring, a crankshaft rotatably mounted in the frame,a ratchet wheel secured to the crankshaft, a pivoted actuator fordriving the ratchet wheel and the crankshaft to charge the spring, amotor for oscillating the actuator, closing latch means for releasablyretaining the spring in the charged condition, tripping latch means,toggle means connected between the tripping latch means and one of theoperating levers on the trip-free shaft, cam means driven by thecrankshaft to extend the toggle means to rotate the trip-free shaft andto close the contact members of said circuit breaker when the closinglatch means is released to release the energy stored in said spring, aspring-biased latch for retaining the toggle means in the extendedposition, and said tripping latch means being re leasable to collapsethe toggle means.

12. In a stored-energy mechanism for actuating contact members of acircuit breaker, in combination, a frame, a trip-free shaft rotatablymounted in the frame, a plurality of operating levers secured to theshaft, operating means for connecting said levers to the breaker contactmembers, a closing spring, a crankshaft rotatably mounted in the frame,a ratchet wheel secured to the crankshaft, a pivoted actuator fordriving the ratchet wheel and the crankshaft to charge the spring, amotor for oscillating the actuator, closing latch means for releasablyretaining the spring in the charged condition, tripping latch means,toggle means connected between the tripping latch means and one of theoperating levers on the trip-free shaft, cam means driven by thecrankshaft to extend the toggle means to rotate the trip-free shaft andto close the contact members of said circuit breaker when the closinglatch means is released to release the energy stored in said spring, aspring-biased latch engaging said toggle means to retain it in itsextended position, and said tripping latch means being releasable tocollapse the toggle means irrespective of the cam means and thespring-biased latch.

13. In a stored-energy mechanism for actuating contact members of acircuit breaker, in combinatioma frame, a trip-free shaft rotatablymounted in the frame, a plurality of operating levers secured to theshaft, operating means for connecting said levers to the breaker contactmembers, a closing spring, a crankshaft rotatably mounted in the frame,means for driving the crankshaft to charge the spring, closing latchmeans for releasably retaining the spring in the charged condition,tripping latch means,

toggle means connected between the tripping latch means and one of theoperating levers on the trip-free shaft, cam

means driven by thecrankshaft to extend the toggle means to rotate thetrip-free shaft and close the contact members of the breaker when theclosing latch means is released to release the energy stored in thespring, accelerating spring means charged during closing of the contactmembers, said tripping latch means being releasable to collapse thetoggle means and permit the accelerating spring means to open thecontact members, and dashpot means connected to at least one of saidoperating levers to reduce shock on the mechanism during opening of thecontact members.

14. In a stored-energy mechanism for actuating contact members of acircuit breaker, in combination, a frame, a trip-free shaft rotatablymounted in the frame, a plurality of operating levers secured to theshaft, operating means for connecting said levers to the breaker contactmembers, a closing spring, a crankshaft rotatably mounted in the frame,means for driving the crankshaft to charge the spring, closing latchmeans for releasably retaining the spring in the charged condition,tripping latch means, toggle means connected between the tripping latchmeans and one of the operating levers on the trip-free shaft, cam meansdriven by the crankshaft to extend the toggle means to rotate thetrip-free shaft and close the contact members of the breaker when theclosing latch means is released to release the energy stored in thespring, accelerating spring means charged during closing of the contactmembers, said tripping latch means being releasable to collapse thetoggle means and permit the accelerating spring means to open thecontact members, and dashpot means connected to the trip-free shaft toreduce shock on the mechanism during closing of the contact members andduring opening of the contact members.

15. In a stored-energy mechanism for actuating contact members of acircuit breaker, in combination, a frame, a trip-free shaft rotatablymounted in the frame, a plurality of operating levers secured to theshaft, operating means for connecting said levers to the breaker contactmembers, a closing spring, a crankshaft rotatably mounted in the frame,means for driving the crankshaft to charge the spring, closing latchmeans for releasably retaining the spring in the charged condition,tripping latch means,

toggle means connected between the tripping latch means and one of theoperating levers on the trip-free shaft, cam means driven by thecrankshaft to extend the toggle means to rotate the trip-free shaft andclose the contact members of the breaker when the closing latch means isreleased to release the energy stored in the spring, accelerating springmeans carried by a shaft having one end pivotally attached to one of theoperating levers, said accelerating spring means being'charged duringclosing of the contact members, said tripping latch means beingreleasable to collapse the toggle means and permit the acceleratingspring means to open the contact members, and dashpot means connected tothe other end of said shaft to reduce shock on the mechanism duringclosing of the contact members and during opening of the contactmembers.

16. In a circuit breaker closing mechanism, a cam rotatable to close thebreaker, said cam having an increasing lobe portion, a roller disposedto engage and follow the cam, a toggle linkage carrying the roller andincluding a tension link and a compression link pivotally connectedtogether, said cam being disposed adjacent to said linkage with thecompressive force in said compression link biasing the roller toward theincreasing lobe portion of the cam, and a releasable restraining linkfor preventing motion of said roller in the latter direction.

17. A circuit breaker closing mechanism, comprising a cam rotatable toclose the breaker, said cam having an increasing lobe portion, a rollerdisposed to engage and follow the cam, a toggle linkage carrying theroller and including a tension link and a compression link pivotallyconnected together, said cam being disposed adjacent to said linkagewith the compressive force in said compression link biasing the rollertoward the increasing lobe portion of the cam, said tension link actingas a releasable restraining link for preventingrnotion of said roller inthe latter direction, and said restraining link being under tensionduring the closing operation.

13. A circuit'breaker closing mechanism, comprising a cam rotatable toclose the breaker, said cam having an increasing lobe portion, a rollerdisposed to engage and follow the cam, a toggle linkage carrying theroller and including a tension link and a compression link pivotallyconnected together, said cam being disposed adjacent to said linkagewith the'compressive force in said compression link biasing the rollertoward the increasing lobe portion of the cam, said tension link actingas a releasable restraining link for preventing motion of said roller inthe latter direction, said restraining link being under tension duringthe closing operation, and trip means for releasing said restraininglink to permit motion of said roller toward said increasing lobe portionof said cam.

19. In a circuit breaker closing mechanism, a cam rotatable to close thebreaker, said cam having an increasing lobe portion, means for rotatingthe earn, a roller disposed to engage and follow the cam, a togglelinkage carrying the roller, said linkage comprising a compression linkand a tension link, said cam being disposed adjacent

1. A STORED-ENERGY MECHANISM COMPRISING A FRAME, A TRIP-FREE SHAFTROTATABLY MOUNTED IN THE FRAME, A CLOSING SPRING, A CRANKSHAFT ROTATABLYMOUNTED IN THE FRAME, MEANS FOR DRIVING THE CRANKSHAFT TO CHARGE THESPRING, CLOSING LATCH MEANS FOR RELEASABLY RETAINING THE SPRING IN THECHARGED CONDITION, CAM MEANS DRIVEN BY THE CRANKSHAFT WHEN SAID CLOSINGLATCH MEANS IS RELEASED TO RELEASE SAID SPRING, TRIPPING LATCH MEANS,TOGGLE MEANS CONNECTED BETWEEN THE TRIPPING LATCH MEANS AND THETRIP-FREE SHAFT, AND SAID TOGGLE MEANS BEING EXTENDED BY SAID CAM MEANSTO ROTATE THE TRIP-FREE SHAFT WHEN THE CLOSING LATCH MEANS IS RELEASEDTO RELEASE THE ENERGY STORED IN SAID SPRING.